The present invention pertains to a cartridge feed mechanism for an automatic firearm, wherein the cartridge feed mechanism is mounted pivotably on a drive housing and a drive sleeve with a coupling groove mounted in the drive housing and a transmission shaft with a coupling tongue is mounted in the cartridge feed mechanism. The coupling tongue engages with the coupling groove in a pivoted-up position of the cartridge feed mechanism and is disengaged from the coupling groove in the pivoted-down position of the cartridge feed mechanism.
Such a cartridge feed mechanism is described in West German Pat. Specification No. 28,25,091. In this prior-art cartridge feed mechanism, the transmission shaft is free when the cartridge feed mechanism is pivoted away from the drive housing. In cases of malfunction, it is necessary to wind the ammunition to and fro at the cartridge feed mechanism. The transmission shaft may then also rotate now. This is unfavorable, because if the cartridge feed mechanism is to be pivoted again to the drive housing, the coupling tongue may be located in a rotated position relative to the coupling groove, in which position it is unable to engage with the coupling groove.